This invention relates to dishwasher machines, and more particularly to a method and apparatus for assembling and securing a motor/pump assembly into a dishwashing machine.
Domestic dishwashing machines are customarily rather compact to save space within the kitchen. This sometimes requires placing components such as the motor and/or pump in positions not readily accessible through the front of the dishwasher. Since an increasing number of dishwashers are installed within kitchen cabinetry (the so-called "built-in" dishwasher), it can be difficult, time consuming, and expensive to service such a dishwasher.
Dishwashers have therefore been designed in which all major parts are accessible from the front. Many such designs, however, still require insertion and removal of one or more major components (such as the motor or pump) from beneath the tank. This requires removing a panel beneath the door to gain access, and then the work must be done in the very cramped space beneath the dishwasher tank. In some cases therefore, even though the component may be accessible through the front of the dishwasher, practical necessity requires that the dishwasher be partially or completely removed from the kitchen cabinet for servicing.
A number of dishwashers have therefore been provided with vertically aligned motor/pump assemblies which can be inserted vertically downwardly from within the dishwasher tank through an opening therefor in the tank bottom. If servicing is then required, these components can be easily removed from the dishwasher by releasing them and then lifting them vertically through the opening into the tank, and then out of the dishwasher. U.S. Pat. No. 3,406,637 (Perl, issued Oct. 22, 1968) shows a motor/pump assembly inserted in this fashion and then secured in conventional manner by screws which fasten the assembly onto a sealing gasket on the rim of the opening in the tank bottom.
Designs such as Perl, however, still have several disadvantages. Assembly by means of screws is time consuming. Further, plastic and rubber materials exhibit flow properties over long periods of time, and rubber materials tend to deteriorate and lose their resiliency. Since higher quality dishwashers are designed for decades of service life, the sealing and clamping force initially provided by the screws can be lost by creeping, flowing and aging of plastic and/or rubber materials over this time. Screw clamp systems, therefore, even when initially properly adjusted, may not provide satisfactory sealing over long periods of time. Furthermore, assembly requires relatively large amounts of time for inserting and tightening the screws, and a degree of care and skill in tightening to the proper tension.
U.S. Pat. No. 3,603,696 (Lampman, issued Sept. 7, 1971) shows a device which overcomes several of the above limitations. The motor/pump assembly in the Lampman dishwasher is also inserted from above into a bottom opening in the tank. Then, a group of resilient retainers are rotated from inwardly directed to outwardly directed positions to engage the underside of the edge of the opening to secure the assembly therein. Here again, however, there is no affirmative provision for securing the motor/pump assembly within the opening with a substantially constant, downward force to provide an adequate and long lasting support and seal for the motor/pump assembly in the bottom of the dishwasher tank.
A need thus remains for an inexpensive motor/pump assembly mounting and supporting configuration for a domestic dishwashing machine which can be quickly attached and secured, which will maintain a substantially constant clamping force over the entire service life of the dishwashing machine, and which will automatically provide the proper force without requiring adjustment by the person doing the assembling.